1. Field of the Invention
The present invention relates to carbon nanocapsules, and more particularly to a carbon nanocapsule thin film.
2. Description of the Related Art
A carbon nanocapsule is a polyhedral carbon cluster constituted by having concentric multi-layers of closed graphitic sheet structure. The diameter of a carbon nanocapsule is about 3-100 nm. There are two types of carbon nanocapsules: hollow and metal-filled. The center of a hollow carbon nanocapsule is leaving a nanoscale cavity, while that of a metal-filled nanocapsule is filled with metals, metal oxides, metal carbides, or alloys.
Carbon nanocapsules were first discovered with carbon nanotubes in 1991, in the process of producing carbon nanotubes. Owing to the strong van der Waals force between carbon nanocapsules and carbon nanotubes, it is not easy to isolate carbon nanocapsules from the carbon nanotubes. In addition, the amount of carbon nanocapsules produced with carbon nanotubes is sufficient only for structural observation under an electron microscope, thus the application thereof is limited.
With continuous research, processes producing high-purity hollow carbon nanocapsules as well as magnetic metal-filled carbon nanocapsules have been developed. (Please refer to U.S. patent application Ser. Nos. 10/255.669 and 10/329.333) In addition to the chemical properties of carbon, with the special hyperfullerene structure and optoelectronic properties of carbon nanocapsules, a carbon nanocapsule thin film is expected to be electric- and heat-conductive, anti-oxidizing, and as structurally stable as graphite; thus it is applicable for an electric- and heat-conductive film, a chemical-resistive and anti-oxidizing protective film, a carbon electrode of an ultra-thin lithium battery and others.
G. A. J. Amaratunga et al, in Hard Elastic Carbon Thin Films from Linking of Carbon Nanoparticle (Nature 383, 321 (1996)), arc-spray carbon nanotubes, hollow carbon nanocapsules and carbon particles on a substrate to form a high-strength mixing carbon film. However, arc-spray must be performed under a very high temperature, and the dispersion of carbon nanocapsules in the mixed carbon film is not uniform. In addition, it is difficult to control the content of carbon nanocapsules in the mixed carbon film.